1. Field of the Invention
The present invention relates generally to an apparatus for cutting or blanking sheet materials such as sheet metals into a number of pieces of various shapes in presses or the like, and more particularly the present invention pertains to an apparatus for blanking from a coiled strip a sheet material into a number of pieces in the form of discs, triangles and other shapes.
2. Description of the Prior Art
In many industries, a coiled strip of a sheet material such as a sheet metal is continuously cut or blanked by a press or the like having upper and lower blanking tools into a number of pieces which are in the form of discs, triangles and other shapes and are usually referred to as blanks. In such a blanking operation, it is of course desired to economically cut the strip into blanks so that the maximum amount of the strip can be utilized to minimize the waste of the strip.
For the purpose of economical blanking, conventionally a wider strip is cut so that a plurality of cuts or blankings are laterally made on the strip in a row normal to the longitudinal edges thereof. Also, when circular disc-like blanks, for example, are to be made from the strip, such a row of the plural cuts are made zigzig or staggered in such a manner that centers of circular cuts of a row will be located in alignment with the midpoints between the circular cuts of the preceding row.
Heretofore, various attempts have been to blank a wider strip so that a plurality of cuts are laterally made on the strip in a row normal to the longitudinal edges thereof. For instance, a plurality of upper and lower blanking tools are grouped into upper and lower sets, respectively, so that a plurality of blanks may be concurrently cut laterally from the strip at each stroke of the upper tools. However, this system will not only required the additional cost for the upper and lower tools but also the larger blanking force that is the larger capacity of the press or the like. Furthermore, this system will make it very often impossible to go on blanking since either of the upper and lower blanking tools is liable to be often broken and also it is time-consuming in changing the upper and lower tools.